Battery, Charging System and Starting System Chevrolet Express G1500

Air Temperature Description and Operation

Description and Operation

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Observe the scan tool Auxiliary Heater Control Module, System Voltage High, System Voltage Low, DTC Set This Ignition parameters will assist you to verify if the fault is present.
Verify that DTC B1425 is set as current.
Engine running measure and record the voltage at the battery terminals.
Verify that the battery voltage is 12.6-15.5 V. If the battery voltage is not within the specified range, refer to «Charging System Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
Observe the scan tool Auxiliary Heater Control Module ignition signal parameter.
The battery terminal and AHCM parameter should not differ by more than 2 V. If greater than specified value, replace the Heater Coolant Heater Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Heater Coolant Heater Control Replacement

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
B+	B1439	B1439
Ground		B1439

The voltages supplied to the control module is between 9.5-18 V.
The ignition is ON.
The engine is running.

HCHCM detects a intermittent system voltage concern.

The control module immediately disables all outputs when an out of range voltage condition has been detected.

The DTC clears when the system voltage returns to a normal range.

Schematic Reference

HVAC Schematics

Connector End View Reference

Air Temperature Description and Operation

Description and Operation

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

A high or low voltage DTC in multiple modules indicates a concern in the charging system.
A possible cause of this DTC could be overcharging with a battery charger or jump starting.
A high voltage value in multiple modules indicates a concern in the charging system.
Inspect G400 for corrosion and proper torque.

Observe the scan tool Auxiliary Heater Control Module, System Voltage High, System Voltage Low, DTC Set This Ignition parameters will assist you to verify if the fault is present.
Verify that DTC B1439 is set as current.
Engine running measure and record the voltage at the battery terminals.
Verify that the battery voltage is 12.6-15.5 V. If the battery voltage is not within the specified range, refer to «Charging System Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Observe the scan tool Auxiliary Heater Control Module ignition signal parameter.
The battery terminal and AHCM parameter should not differ by more than 2 V.
Ensure the harness connections at the module are fully seated and secure, inspect for bent terminals and corrosion.

Circuit/System Testing

Ignition OFF, disconnect the harness connector at the Heater Coolant Heater Control Module (HCHCM).
Ignition OFF, test for less than 3.0 ohms between the ground circuit terminal H X2 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
Ignition ON, verify a test lamp illuminates between the B+ voltage circuit terminal A X2 and ground. If the test lamp does not illuminate, test the B+ voltage circuit for a short to ground or an open/high resistance.
If all circuits test normal, replace the Heater Coolant Heater Control Module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Heater Coolant Heater Control Replacement

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
5-Volt Reference	B1516 08	B1516 08
Signal	B1516 08	B1516 08	B1516 08	B1516 08, B1516 66
Low Reference		B1516 08

The battery current sensor is a 3-wire hall effect current sensor. The body control module (BCM) supplies 5 V and ground to the battery current sensor. The battery current sensor measures the amount of current flowing to or from the battery, and supplies a pulse width modulation (PWM) signal to the BCM. The BCM monitors the battery current signal, and sets DTC B1516 08 if the signal is outside the normal range if 4-96 percent duty cycle. The BCM also monitors the current polarity, and sets DTC B1516 66 if reverse polarity is detected.

B1516 08

The BCM is awake.

B1516 66

The BCM is awake.
The engine is OFF.

B1516 08

The battery current signal is less than 4 percent or greater than 96 percent duty cycle for 2 minutes.

B1516 66

The battery current polarity is positive for 2 minutes.

The regulated voltage control (RVC) is disabled.

The DTC passes when the battery current returns to the normal range for 15 seconds.

DTC B1516 08 could be set by overcharging with a battery charger or jump starting.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

B1516 08

Ignition OFF, disconnect the harness connector at the battery current sensor.
Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the low reference circuit terminal B and ground. If greater than specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the BCM.
Ignition ON, test for 4.8-5.2 V between the 5-volt reference circuit terminal A and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests, normal replace the BCM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests, normal replace the BCM.
Ignition ON, test for 4.8-5.2 V between the signal circuit terminal C and ground. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
If all circuits test normal, test or replace the battery current sensor.

B1516 66

Verify that the battery current sensor is installed securely around the negative battery cable, with the tape tab pointing away from the negative terminal on the battery. If the battery current sensor is not installed correctly, remove and reinstall the sensor properly.
Replace the battery current sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Battery Current Sensor Replacement»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) for current sensor replacement
«Control Module References»(/chevrolet/express-g1500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance
B+	B1517	B1517
B+ high resolution	B1517	B1517
Ground		B1517

The body control module (BCM) has designated circuits for monitoring vehicle system voltage. The BCM monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range. The BCM monitors the system voltage over an extended length of time. If the BCM detects the system voltage is outside an expected range for the calibrated length of time, or the BCM battery sense circuits differ by 2 V, DTC B1517 will set. Other modules also monitor system voltage the system voltage message is sent to the other modules and will default to 12.9 V.

The DTC shall run only if the BCM has power, ground, and the ignition is not in the START mode. This DTC shall execute regardless of battery voltage.

B1517 03

The battery voltage falls below 11 V, engine speed greater than 1, 100 RPM for 15 seconds.

B1517 07

The battery voltage is greater than 16 V, engine speed greater than 1, 100 RPM for 15 seconds.

B1517 5A

The battery voltage differs by 2 V on the BCM battery sense circuits for 10 seconds.

The driver information center (DIC) displays the SERVICE BATTERY CHARGING SYSTEM warning message and the Charge Indicator on the instrument panel cluster (IPC) illuminates.

The DTC will clear current status when fault is no longer present.
The history DTC will clear after 50 consecutive ignition cycles have occurred without a malfunction.

A high or low voltage DTC set in multiple modules indicates a concern in the charging system.
A possible cause of this DTC could be overcharging with a battery charger or jump starting.
A high or low voltage value in multiple modules indicates a concern in the charging system.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Engine running, accessories OFF, measure and record the voltage at the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 V. If not within the specified range, refer to «Charging System Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
Observe the scan tool BCM Battery Voltage parameter. The reading should be between 12.6 and 15.0 V.

Ignition OFF, disconnect the harness connectors at the BCM.
Ignition OFF, test for less than 3.0 ohms between the ground circuit terminals listed below and ground. Terminal 1 X3 Terminal 5 X3 If not within the specified range, test the appropriate ground circuit for an open/high resistance.
Ignition On, verify a test lamp illuminates between the B+ circuits terminals listed below and ground. Terminal 3 X3 Terminal 10 X4 If the test lamp does not illuminate, test the appropriate B+ circuit for a short to ground or an open/high resistance.
If all circuits test normal, replace the BCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The body control module (BCM) monitors the state of charge of the electrical system.

The ignition is in Accessory or Run mode.

The state of charge at ignition ON is 30% lower than when the engine was running and battery drain is more than 2 A.

There is no battery telltale illuminated or DIC message displayed.

The DTC will clear if the fault does not return after 50 consecutive ignition cycles.
The DTC will clear when run state of charge is greater than or equal to 80%.

Schematic Reference

Connector End View Reference

Description and Operation

Antilock Brake System Schematics

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Refer to Battery Electrical Drain/Parasitic Load Test .

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
B+	C0899 03	C0899 03
Ground		C0899 03

Typical Scan Tool Data

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Ignition ON, engine OFF. Parameter Normal Value: 12.60 Volts
B+	0.00 Volts	0.00 Volts	12.60 Volts

Battery Voltage Signal

The electronic brake control module (EBCM) monitors the battery voltage available for system operation. A high or low voltage condition prevents the system from operating properly.

Ignition ON

C0899 03

The EBCM detects that the battery voltage is less than 9 V for 1 second.

C0900 07

The EBCM detects that the battery voltage is greater than 16.8 V for 1 second.

C0899 03

The antilock brake system (ABS), traction control system (TCS), and vehicle stability enhancement system (VSES) are disabled.
The dynamic rear proportioning (DRP) is disabled, if the battery voltage is less than 6.9 volts.
The ABS, traction control, and vehicle dynamics caution (VDC) indicators turn ON.
The DIC displays the TRACTION CONTROL OFF message 1 time.
The DIC displays the SERVICE STABILITRAK and SERVICE TRACTION CONTROL messages.

C0900 07

The ABS, DRP, TCS, and VSES are disabled.
The ABS, BRAKE, and traction control indicators turn ON.
The DIC displays the TRACTION CONTROL OFF message 1 time.
The DIC displays the SERVICE STABILITRAK and SERVICE TRACTION CONTROL messages.

C0899 03

The system voltage returns above 9 V for 1 second.

C0900 07

The system voltage returns to less than 16.8 V for 1 second.

A high or low voltage DTC in multiple modules indicates a concern in the charging system.
DTC C0900 could be set by overcharging with a battery charger or jump starting.
The ABS, BRAKE, and traction control indicators may turn ON without any DTCs set, if the EBCM detects that the battery voltage is less than 9 V, and the vehicle speed is less than 6 km/h (3.7 mph).

Schematic Reference

Connector End View Reference

Engine Controls Schematics

Description and Operation

«ABS Description and Operation»(/chevrolet/express-g1500/2013-2013/remont/anti-locktraction-control/#antilock-brake-system__abs-description-and-operation)
«Rear Drive Axle Description and Operation»(/chevrolet/express-g1500/2013-2013/remont/differentials-drive-axles/#rear-drive-axle)

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6-15.0 V. If not within the specified range, refer to «Charging System Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Observe the scan tool Battery Voltage Signal parameter. The reading should be between 12.6-15.0 V.

Ignition OFF, disconnect the harness connector at the EBCM.
Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the ground circuit terminals listed below and ground. Terminal 11 Terminal 28 If greater than the specified range, test the ground circuit for an open/high resistance.
Verify that a test lamp illuminates between the B+ circuit terminals listed below and ground. Terminal 1 Terminal 18 If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
If all circuits test normal, replace the EBCM.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for appropriate control module replacement, programming, and setup.

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
B+	P0562	P0562
Ground		P0562

The fuel pump control module (FPCM) monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range.

The engine is running.

The FPCM detects that the battery voltage is less than 9 V.

DTC P0562 is a type C DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 V. If not within the specified range, refer to «Charging System Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Ignition OFF, disconnect the harness connectors at the FPCM.
Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the ground circuit terminal 1 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
Verify that a test lamp illuminates between the B+ circuit terminal 32 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
If all circuits test normal, replace the FPCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for FPCM replacement, setup, and programming.

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
IGN I	P0562	P0562
Ground		P0562

The engine control module (ECM) monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range.

The vehicle speed is above 8 km/h (5 mph).
The system voltage is between 9.5-18 V.

The ECM detects a system voltage below 10 V.

The instrument panel cluster (IPC) illuminates the charge indicator.
The driver information center (DIC) displays the SERVICE BATTERY CHARGING SYSTEM warning message.

DTC P0562 is a C type DTC.

A low voltage DTC in multiple modules indicates a concern in the charging system.
A low voltage value in multiple modules indicates a concern in the charging system.
Inspect the ECM ground connection, to verify that it is clean tight.

Schematic Reference

«Engine Controls Schematics»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-wiring-schematic-diagrams) for the 4.3L engine
«Engine Controls Schematics»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-wiring-schematic-diagrams) for V8 gas engines
«Engine Controls Schematics»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-wiring-schematic-diagrams) for the 6.6L engine

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Engine running measure and record the voltage at the battery terminals. Verify that the battery voltage is 12.6-15.5 V. If the battery voltage is not within the specified range, refer to «Charging System Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Observe the scan tool ECM Ignition 1 Signal parameter. The reading should be between 12.6 and 15.0 V.

Ignition OFF, disconnect the harness connectors at the ECM.
Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 ohms between the ground circuit terminals listed below and ground: 4.3L terminal 73 X2. V8 gas engines terminal 73 X1. 6.6L terminals 2-4 and 6 X2. If greater than the specified range, test the ground circuit(s) for an open/high resistance.
Verify that a test lamp illuminates between the B+ circuit terminals listed below and ground. 4.3L terminals 19 and 73 X1. V8 gas engines X1 terminals 19 and 47 X1. 6.6L terminal 77 X1 and terminals 1-3-5 X2. If the test lamp does not illuminate, test the Ignition circuits for a short to ground or an open/high resistance.
If all circuits test normal, replace the ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
B+	P0562	P0562
Ground		P0562

The ignition is ON.

The FPCM detects that the system voltage is greater than 17.5 V.

DTC P0563 is a type C DTC.

A high voltage DTC in multiple modules indicates a concern in the charging system.
This DTC could be set by overcharging with a battery charger or jump starting.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 V. If not within the specified range, refer to «Charging System Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
If all circuits test normal, replace the FPCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for FPCM replacement, setup, and programming.

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
IGN I	P0562	P0562
Ground		P0562

The vehicle speed is above 8 km/h (5 mph).
The system voltage is between 9.5-18 V.

The ECM detects a system voltage above 16 V.

DTC P0563 is a C type DTC.

A possible cause of this DTC could be overcharging with a battery charger or jump starting.
A high voltage value in multiple modules indicates a concern in the charging system.

Schematic Reference

«Engine Controls Schematics»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-wiring-schematic-diagrams) for the 4.3L engine
«Engine Controls Schematics»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-wiring-schematic-diagrams) for V8 gas engines
«Engine Controls Schematics»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-wiring-schematic-diagrams) for the 6.6L engine

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Verify DTC P0563 is set as current.
Engine running measure and record the voltage at the battery terminals. Verify that the battery voltage is 12.6-15.5 V. If the battery voltage is not within the specified range, refer to «Charging System Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Engine running, observe the scan tool ECM Ignition 1 signal parameter.
Verify the battery and Ignition 1 signal readings do not differ more than 2.0 V. If greater than specified value, replace the ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
Control	P0615, P0616*	P0615, P0616*	P0615, P0617*
Ground		P0615, P0616*
* 4.3L, 4.8L, or 5.3L ** 6.6L Diesel

When the ignition switch is placed in the START position, a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the START position. The BCM then sends a message to the engine control module (ECM) that crank has been requested. The ECM then verifies that the clutch pedal is depressed or the transmission is in Park/Neutral. If it is, the ECM then supplies 12 V to the control circuit of the starter relay. When this occurs, battery voltage is supplied through the switch of the starter relay to the starter solenoid.

The ignition is in the START position.
The system voltage is between 9.5-18 V.

The ECM detects improper voltage on the control circuit of the starter relay.

DTC P0615, P0616, and P0617 are C type DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition OFF, disconnect the starter relay.
Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5.0 ohms between the relay ground circuit terminal 85 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
Verify a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground.
Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
Parking brake applied and the transmission is in NEUTRAL or PARK. Momentarily install a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the starter motor is activated. If the starter motor does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the starter motor.
Ignition OFF, connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
Transmission in park or neutral, command the starter relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for short to voltage. If the circuit tests normal, replace the ECM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
If all circuits tests normal, replace the starter relay.

Component Testing

Relay Test

Ignition OFF, disconnect the starter relay.
Test for 60-180 ohms between terminals 85 and 86. If not within the specified range, replace the relay.
Test for infinite resistance between the following terminals: 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified value, replace the relay.
Install a 20 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Relay Replacement (Within an Electrical Center)»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) , «Relay Replacement (Attached to Wire Harness)»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
«Control Module References»(/chevrolet/express-g1500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The ECM monitors the state of the charge indicator control circuit. The ECM should detect a low circuit voltage when the key is ON and the engine is OFF, or when the charging system malfunctions. With the engine running, the ECM should detect a high circuit voltage. The ECM performs key ON and RUN tests to determine the status of the charge indicator control circuit.

During the key ON test, if the ECM detects a high circuit voltage, DTC P0621 will set. DTC P0621 will also set if, during the RUN test, the ECM detects a low circuit voltage. When the DTC sets, the IPC will illuminate the charge indicator or a warning message will be displayed in the driver information center (DIC) if equipped.

Key ON Test

No generator, crankshaft position (CKP) sensors, or camshaft position (CMP) sensor DTCs are set.
The ignition is in RUN position.
The engine is not running.

RUN Test

No generator, CKP sensors, CMP sensor DTCs are set.
The engine is running.

During the key ON test, the ECM detects high voltage on the charge indicator control circuit for at least 5 seconds. OR during the RUN test the ECM detects low voltage on the charge indicator control circuit for at least 15 seconds.

DTC P0621 is a C type DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing - Single Generator (w/o KD9)

Verify that a test lamp illuminates between the G13 generator B+ terminal 1 X2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF. Test for greater than 100 ohms between the B+ circuit and ground. If 100 ohms or less, repair the short to ground on the circuit. If greater than 100 ohms, replace the generator. If the test lamp illuminates
Ignition OFF, disconnect the X1 harness connector at the generator, ignition ON.
Test for 3.5V or greater between the control circuit terminal B X1 and ground. If less than 3.5V Ignition OFF, disconnect the harness connectors at the ECM. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If greater than 2 ohms, repair the open/high resistance in the circuit. If less than 2 ohms, replace the ECM. If 3.5V or greater Ignition OFF, disconnect the harness connectors at the ECM. Test for less than 1 V between the control circuit and ground. If less than 1 V, replace the Generator. If 1 V or greater, repair the short to voltage on the circuit.

Circuit/System Testing- Dual generators (w/ KD9)

Verify that a test lamp illuminates between the each generator B+ terminal 1 X2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF. Test for less than 2 ohms in each B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF. Test for greater than 100 ohms between the B+ circuit and ground. If 100 ohms or less, repair the short to ground on the circuit. If greater than 100 ohms, replace the appropriate generator. If the test lamp illuminates
Ignition OFF, disconnect the X1 harness connectors at both generators, ignition ON.
Test for 3.5V or greater between the control circuit terminal B X1 and ground. If less than 3.5V Ignition OFF, disconnect the harness connectors at the ECM. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If greater than 2 ohms, repair the open/high resistance in the circuit. If less than 2 ohms, replace the ECM. If 3.5V or greater Ignition OFF, disconnect the harness connectors at the ECM. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF, connect X1 harness connector at the auxiliary generator, Ignition ON. Test for less than 1 V between the control circuit and ground. If greater than 1 V, replace the auxiliary generator. If less than 1 V Ignition OFF, connect the harness connectors at the ECM. Engine running, test for 3.5 V or greater between the generator control circuit terminal B X1 and ground. If less than 3.5 V, test or replace the auxiliary generator. If 3.5 V or greater, test or replace the generator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Auxiliary Generator Replacement»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Control Module References»(/chevrolet/express-g1500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
B+	P0622	P0621
Control - L Terminal	P0621	P0621	P0621
Signal - F Terminal	P0622	P0622	P0622	P0622

The engine control module (ECM) uses the generator turn ON control circuit to control the load of the generator on the engine. A high side driver in the ECM applies a duty cycled voltage to the voltage regulator. The duty cycle controls the voltage regulator to turn the field circuit ON and OFF. The ECM monitors the state of the generator turn ON control circuit. The ECM should detect low voltage on the generator turn on control circuit when the ignition is ON and the engine is OFF, or when the charging system malfunctions. With the engine running, the ECM should detect high voltage when the duty cycle voltage is commanded high and a low voltage when the duty cycle voltage is commanded low on the generator turn on control circuit.

Ignition ON, engine OFF (Prior to Ignition ON, the ignition must have been OFF for at least 5 seconds)
The engine is running for the run test

Ignition ON, engine OFF - The ECM detects greater than 3.5 V on the generator control circuit for 5 seconds
Engine running - The ECM detects a low voltage for 15 seconds on the generator control circuit when the duty cycle voltage is commanded high
Engine running - The ECM detects a high voltage for 15 seconds on the generator control circuit when the duty cycle voltage is commanded low
Operate vehicle within the conditions defined in the records to verify the DTC does not reset

DTC P0621 is a C type DTC

Ignition ON, engine OFF- Low voltage
Engine running - A control signal duty cycle is detected

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Verify the DTC does not set. If the DTC sets Refer to Circuit/System Testing below. If the DTC does not set
All OK.

Verify a test lamp illuminates between the G13 Generator B+ circuit terminal 1 X2 and ground. If the test lamp does not illuminate and the circuit fuse is good Remove the test lamp and disconnect the B+ cable at the G13 Generator. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Remove the test lamp, disconnect the battery negative cable, and disconnect the G13 Generator B+ cable. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If the test lamp illuminates
Disconnect the X1 harness connector at the G13 Generator.
Engine Running, test for 3.0- 5.5 V between the control circuit terminal B and ground. If less than 3.0 V Ignition OFF, disconnect the harness connectors at the K20 Engine Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If greater the 2 ohms, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 Engine Control Module. If greater than 5.5 V Ignition OFF, disconnect the harness connectors at the K20 Engine Control Module, Ignition ON. Test for less than 1 V between the control circuit and ground. If greater than 1 V, repair the short to voltage on the circuit. If less than 1 V, replace the K20 Engine Control Module. If between 3.0-5.5 V
Test or replace the G13 Generator.

Perform the Diagnostic Repair Verification after completing the repair.

«Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Control Module References»(/chevrolet/express-g1500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Engine Control Module replacement, programming, and setup

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
B+	P0622	P0621
Control - L Terminal	P0621	P0621	P0621
Signal - F Terminal	P0622	P0622	P0622	P0622

Ignition ON, engine OFF (Prior to Ignition ON, the ignition must have been OFF for at least 5 seconds)
The engine is running for the run test

Ignition ON, engine OFF - The ECM detects greater than 3.5 V on the generator control circuit for 5 seconds
Engine running - The ECM detects a low voltage for 15 seconds on the generator control circuit when the duty cycle voltage is commanded high
Engine running - The ECM detects a high voltage for 15 seconds on the generator control circuit when the duty cycle voltage is commanded low
Operate vehicle within the conditions defined in the records to verify the DTC does not reset

DTC P0621 is a C type DTC

Ignition ON, engine OFF- Low voltage
Engine running - A control signal duty cycle is detected

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Verify the DTC does not set. If the DTC sets Refer to Circuit/System Testing below. If the DTC does not set
All OK.

Verify a test lamp illuminates between the G13 Generator B+ circuit terminal 1 X2 and ground. If the test lamp does not illuminate and the circuit fuse is good Remove the test lamp and disconnect the B+ cable at the G13 Generator. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Remove the test lamp, disconnect the battery negative cable, and disconnect the G13 Generator B+ cable. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If the test lamp illuminates
Disconnect the X1 harness connector at the G13 Generator, ignition ON.
Test for 3.0- 5.5 V between the control circuit terminal B and ground. If less than 3.0 V Ignition OFF, disconnect the harness connectors at the K20 Engine Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the control circuit end to end. If greater the 2 ohms, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 Engine Control Module. If greater than 5.5 V Ignition OFF, disconnect the harness connectors at the K20 Engine Control Module, Ignition ON. Test for less than 1 V between the control circuit and ground. If greater than 1 V, repair the short to voltage on the circuit. If less than 1 V, replace the K20 Engine Control Module. If between 3.0-5.5 V
Test or replace the G13 Generator.

Perform the Diagnostic Repair Verification after completing the repair.

«Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Control Module References»(/chevrolet/express-g1500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Engine Control Module replacement, programming, and setup

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
B+	P0622	P0621
Control - L Terminal	P0621	P0621	P0621
Signal - F Terminal	P0622	P0622	P0622	P0622

The engine control module (ECM) uses the generator field duty cycle signal circuit, or F-terminal circuit, to monitor the duty cycle of the generator. The generator field duty cycle signal circuit connects to high side of the field windings in the generator. A pulse width modulated (PWM) high side driver in the voltage regulator turns the field windings ON and OFF. The ECM uses the PWM signal input to determine the generator load on the engine. This allows the ECM to adjust the idle speed to compensate for high electrical loads. The ECM monitors the status of the generator field duty cycle signal circuit. When the ignition is ON and the engine is OFF, the ECM should detect a duty cycle near 0%. When the engine is running, the duty cycle should be between 5-99%.

Ignition ON, engine OFF (Prior to Ignition ON, the ignition must have been OFF for at least 5 seconds).
Engine running at less than 3, 000 RPM.

DTC P0621 is not set.
Ignition ON, engine OFF (Prior to Ignition ON, the ignition must have been OFF for at least 5 seconds), the ECM detects a PWM signal that is greater than 65% for 5 seconds.
Engine running at less than 3, 000 RPM - The ECM detects a PWM signal that is less than 5% for 30 seconds.

DTC P0622 is a C type DTC.

Ignition ON, Engine OFF- Low / no PWM signal detected.
Engine running - A 5-90% duty cycle is detected.

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Note. Do not have a battery charger connected during the generator testing.

Engine running.
Verify the scan tool Engine Control Module Generator F-Terminal Signal parameter is between 5-90%. If not between 5-90% Refer to Circuit/System Testing below. If between 5-90%
Verify the scan tool Engine Control Module Generator F-Terminal Signal parameter changes when commanding the headlamps ON and OFF. If the parameter does not change Refer to Circuit/System Testing below. If the parameter changes
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Verify the DTC does not set. If the DTC sets Refer to Circuit/System Testing below. If the DTC does not set
All OK.

Verify a test lamp illuminates between the G13 Generator B+ circuit terminal 1 X2 and ground. If the test lamp does not illuminate and the circuit fuse is good Remove the test lamp and disconnect the B+ cable at the G13 Generator. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Remove the test lamp, disconnect the battery negative cable, and disconnect the G13 Generator B+ cable. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If the test lamp illuminates
Disconnect the X1 harness connector at the G13 Generator, engine running.
Verify the scan tool Engine Control Module Generator F-Terminal Signal parameter is less than 5%. If 5% or greater Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON. Test for less than 1 V between the signal circuit terminal 2 or C and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K20 Engine Control Module. If less than 5%
Install a 3 A fused jumper wire between the signal circuit terminal 2 or C and B+.
Engine running, verify the scan tool Engine Control Module Generator F-Terminal Signal parameter is greater than 95%. If 95% or less Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module. Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms Test for infinite resistance between the signal circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K20 Engine Control Module. If greater than 95%
Test or replace the G13 Generator.

Perform the Diagnostic Repair Verification after completing the repair.

«Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Control Module References»(/chevrolet/express-g1500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Engine Control Module replacement, programming, and setup

Symptoms - Engine Electrical

Note. The following steps must be completed before using the symptom tables.

Perform «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
Review the system descriptions and operations in order to familiarize yourself with the system functions. Refer to one of the following system operations: «Battery Description and Operation»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system__battery-description-and-operation) «Charging System Description and Operation»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) «Electrical Power Management Description and Operation (Gasoline)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system__electrical-power-management-description-and-operation) , «Electrical Power Management Description and Operation (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system__electrical-power-management-description-and-operation) «Starting System Description and Operation»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system__starting-system-description-and-operation)

Visual/Physical Inspection

Inspect for aftermarket devices which could affect the operation of the starting and charging systems. Refer to «Checking Aftermarket Accessories»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

«Battery Inspection/Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Battery Electrical Drain/Parasitic Load Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Charging System Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Generator Noise Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Starter Solenoid Does Not Click»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Starter Solenoid Clicks, Engine Does Not Crank»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Engine Cranks Slowly»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Starter Noise Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Note. For Warranty repairs - You must use regionally required battery test equipment for warranty repairs. For accurate test results the battery must be disconnected from the vehicle and the equipment connected directly to the battery posts. When setting up the equipment, select "Out of Vehicle" and then the correct battery type (Flooded or AGM) and rated CCA (both from the battery label) must be entered. Failure to obtain the correct connections during the test may result in a failed test on a good battery. Use the Out of Vehicle test (both batteries disconnected with test equipment connected directly to the post) test for each battery when testing a vehicle with dual batteries.

Follow these instructions in order to avoid an incorrect diagnosis because of connections

If testing the vehicle with the battery cables still connected, wiggle the battery tester clips on the terminal. This may cut through any coating or through any oxidation that may be present on the terminal.
If correct connections to the battery terminals in the vehicle are in doubt, perform the following steps: Disconnect the negative battery cable. Disconnect the positive battery cable. Follow the instructions for testing a removed battery.
If the tester displays a REPLACE BATTERY or BAD CELL-REPLACE result for a battery tested in the vehicle with the battery cables connected, perform the following steps: Disconnect the negative battery cable. Disconnect the positive battery cable. NOTE: Always write the test code displayed by the tester on the repair order for any warranty purposes. The number is a unique code that describes the test data for a particular battery at a particular time. The test code may occasionally repeat when you retest the same battery. More often, each test will result in a different code. Use the test code from the second, or Out of Vehicle test. Follow the instructions for testing a removed battery. Replace the battery only if the second test shows a REPLACE BATTERY or BAD CELL-REPLACE result. Use the test code from the second test for any warranty purposes.

Schematic Reference

Connector End View Reference

Description and Operation

Battery Replacement (Primary)

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL 50313 Battery Tester

WARNING

Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components. For Vehicles equipped with OnStar® (UE1) with Back Up Battery: The Back Up Battery is a redundant power supply to allow limited OnStar® functionality in the event of a main vehicle battery power disruption to the VCIM (OnStar®module). Do not disconnect the main vehicle battery or remove the OnStar® fuse with the ignition key in any position other than OFF. Retained accessory power should be allowed to time out or be disabled (simply opening the driver door should disable retained accessory power) before disconnecting power. Disconnecting power to the OnStar® module in any way while the ignition is On or with retained accessory power activated may cause activation of the OnStar® Back-Up Battery system and will discharge and permanently damage the back-up battery. Once the Back-Up Battery is activated it will stay on until it has completely discharged. The back-up battery is not rechargeable and once activated the back-up battery must be replaced.

Verify the C1 Battery case is not cracked, broken, or damaged, which may be indicated by battery acid leakage. If there is any apparent damage Replace the C1 Battery. If there is no damage
Verify the cold cranking amperage and amperage hour rating of the C1 Battery. Refer to the manufacturer specifications on the battery label. If the C1 Battery does not meet specifications Replace the C1 Battery. If the C1 Battery meets specifications
Verify that the battery cables are clean and tight. The battery terminal bolts should be torqued as specified in «Fastener Tightening Specifications»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system__fastener-tightening-specifications) . If the battery cables need to be cleaned or tightened Clean as required and tighten as specified. If the battery cables are clean and tight
Install the battery tester and follow directions supplied by the tester.

Perform the Diagnostic Repair Verification after completing the repair.

Special Tools

EL 50313 Battery Tester

For equivalent regional tools, refer to Special Tools .

For best results, use an automatic taper-rate battery charger with a voltage capability of 16 V.
The charging area should be well ventilated.
Do not charge a battery that appears to be frozen. Allow the battery to warm to room temperature and test it using the EL 50313 Battery Tester before charging.

Battery State of Charge

Note. Using voltage to determine the batteries state of charge is only accurate after the battery has been at rest for 24 hours. This is enough time for the acid in each cell to equalize. If the battery has been charged or discharged in the past 24 hours, the battery state of charge will only be an estimate.

The maintenance-free batteries state of charge is estimated by reading the voltage of the battery across the battery terminals. Because the voltage is affected by current flow into or out of the battery, the engine must be stopped and all electrical loads turned OFF, including parasitic loads, when checking the voltage. The voltage can also be affected if the battery has just been charged or discharged, so it is important to consider what has happened to the battery in the time just before testing. Use the following procedure to determine the batteries state of charge

Be sure all electrical loads are turned OFF.
Determine whether the battery has been used in a vehicle or charged within the past 12 hours. If the answer is no, the terminal voltage will be stabilized and no action is necessary before reading the voltage. Skip to step 3. If the answer is yes, terminal voltage will not be stabilized and you should wait 12 hours since the last time the battery was used.
Estimate the battery temperature by determining the average temperature to which the battery has been exposed for the past 12 hours.
Measure the battery voltage at the battery terminals. Refer to the following table to determine the state of charge according to the estimated battery temperature

Battery Voltage	% Charge at 0°C (32°F)	% Charge at 25°C (75°F)
12.75 V	100%	100%
12.7 V	100%	90%
12.6 V	90%	75%
12.45 V	75%	65%
12.2 V	65%	45%
12.0 V	40%	20%

Battery Charging

Use the state of charge information as follows

A battery with a state of charge that is below 65 percent must always be recharged before returning it to service or continuing storage.
A battery with a state of charge that is 65 percent or greater is generally considered to be charged enough in order to be returned to normal service or in order to continue storage. However, if the battery is being used in slow traffic or with short drive times, or if the temperature is very hot or very cold, the battery should be fully charged, to at least 90 percent, before returning it to service or continuing storage.

Charging Time Required

The time required to charge a battery will vary depending upon the following factors

The battery charger capacity-The higher the charger amperage, the less time it will take to charge the battery.
The state of charge of the battery-A completely discharged battery requires more than twice as much charging time as a half charged battery. In a discharged battery with a voltage below 11 V, the battery has a very high internal resistance and may only accept a very low current at first. Later, as the charging current causes the acid content to increase in the electrolyte, the charging current will increase. Extremely discharged batteries may not activate the reversed voltage protection in some chargers. Refer to the manufacturer's instructions for operating this circuitry.
The temperature of the battery-The colder the battery is, the more time it takes to recharge the battery. The charging current accepted by a cold battery is very low at first. As the battery warms, the charging current will increase.

Charging Procedure

CAUTION

Turn OFF the ignition when connecting or disconnecting the battery cables, the battery charger or the jumper cables. Failure to do so may damage the ECM/PCM or other electronic components.

CAUTION

Refer to Fastener Caution .

When charging side-terminal batteries with the battery cables connected, connect the charger to the positive cable bolt and to a ground located away from the battery. When charging side-terminal batteries with the battery cables disconnected, install the battery side terminal adapters and connect the charger to the adapters.

Tighten

Tighten the battery side terminal adapters to 15 N.m (11 lb ft).

Use the following procedure to charge the battery

Turn OFF the charger.
Ensure that all of the battery terminal connections are clean and tight.
Connect the charger positive lead to the battery positive terminal on the battery or the remote jumper stud underhood.
Connect the negative charger lead to a solid engine ground or to a ground stud in the engine compartment that is connected directly to the battery negative terminal, but away from the battery. If the negative battery cable is disconnected and a terminal adapter is being used, connect directly to the adapter.
Turn ON the charger and set to the highest setting for normal charging.
Inspect the battery every half hour after starting the battery charger. Charge the battery until the taper-rate charger indicates that the battery is fully charged. Estimate the battery temperature by feeling the side of the battery. If it feels hot to the touch or its temperature is over 45°C (125°F), discontinue charging and allow the battery to cool before resuming charging.
After charging, test the battery. Refer to «Battery Inspection/Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

12 V Battery

The following procedure is for the 12 V battery only.

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Components most likely to cause a parasitic draw on the vehicles battery are switches, relays, and control modules. After the ignition is turned OFF the control modules will begin to go to sleep shut OFF. All control modules do not go to sleep at the same time, some may take up to 30 min or longer after turning the ignition off before going to sleep. Other modules may periodically wake up then go back to sleep. These are all normal conditions.

Rule out any possible aftermarket equipment causing an unacceptable parasitic current drain. Aftermarket accessories installed into the courtesy lamp circuit can cause the inadvertent power timer in the body control module (BCM) to keep resetting. This may cause the BCM to remain awake and cause a current drain on the battery.
Rule out customer driving habits such as regular short trips that do not allow enough time to properly charge the battery. Refer to «Battery Description and Operation»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system__battery-description-and-operation) .
Verify that the battery and charging system are in proper working order. Refer to «Battery Charging»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , and «Charging System Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
A battery discharging for no apparent reason while the vehicle is parked can be caused by an intermittent draw, such as a module waking up, or a continuous draw, such as a dome light or stuck relay.
Some systems and modules such as OnStar®, and regulated voltage control, if equipped, are designed to wake up, perform a task, and go back asleep at regular intervals. Refer to «Body Control System Description and Operation»(/chevrolet/express-g1500/2013-2013/remont/communication-devices/#data-communication-system__body-control-system-description-and-operation) for the system or modules description and operation.
An engine off natural vacuum evaporative test can occur if the engine control module (ECM) determines the drive cycle has met the appropriate criteria immediately after key off. The ECM will stay awake and the vent solenoid will stay energized for as long as 45 min. The typical current draw for this is about 1 A.
Digital OnStar generation 6 and later vehicle communication interface module do not "wake up" every 10 min for the first 48 h as the generation 5 and prior. generation 6 and later vehicle communication interface module current draw is very low, less than 40 mA, so the OnStar system is left in that state for up to the first 48 h. Parasitic draw of up to 40 mA with an occasional spike as high as 80 mA through the vehicle communication interface module for the first 48 h is normal.
Some automatic climate control systems can remain in a semi awake state for up to three hours, actual draw amounts vary by vehicle platform but are typically not greater than 50 mA.
An extremely low mA current level is consumed by the remote keyless entry receiver for monitoring purposes, actual system wake up only occurs when the fobs for the vehicle are used. When other devices on the same remote keyless entry operating frequency are activated, such as the 4 tire pressure monitoring sensors and other vehicle FOBs in the vicinity, the remote keyless entry receiver will have a 100 mA spike. These spikes are normal and occur too briefly to have a significant effect on battery drain. Competing signals may cause remote keyless entry performance issues such as jamming but should not cause excessive battery draw.
If an excessive current draw is not present during initial testing, continue periodic testing over a 1-2 hour period to see if the current draw increases and stays above an unacceptable level.
The battery run down time will vary depending on the batteries reserve capacity. If the reserve capacity is higher, then the battery run down time may be longer. If the reserve capacity is lower, then the battery run down time may be shorter. The graph below indicates roughly how many days a 690 cold cranking amperage battery with a 110 min reserve capacity starting at 80% state of charge will last with a constant current draw until it reaches 50% state of charge. Differences in battery reserve capacity and temperature will affect the results.

Current Drain	Days
25 mA	33
50 mA	16.5
75 mA	11
100 mA	8.25
250 mA	3.3
500 mA	1.65
750 mA	1
1 A	0.8
2 A	0.4

Schematic Reference

Control Module References

Connector End View Reference

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL 38758 Parasitic Draw Test Switch

For equivalent regional tools, refer to Special Tools .

Note. Most vehicle systems will go to sleep within 30 min but it can take up to 2 h before all systems power down allowing the parasitic draw test to pass. An occasional increase in the parasitic draw is normal as long as it returns within 1 s. Closing the door latches/ajar switch while leaving the doors open is recommended, this allows the vehicle systems to perform in a "doors closed" mode while allowing vehicle interior access that may be needed to complete the diagnostic steps. Locking doors will arm the vehicle content theft deterrent system if equipped. Failure to arm the system may cause a theft system fault to not be present during testing. There are many things that can prevent the vehicle from completely going to sleep and passing the parasitic draw test. Make sure all the conditions listed below are met before performing the parasitic current draw test. Ignition OFF Key out of the ignition switch - when not equipped with keyless access and start Retained Accessory Power OFF - open and close the driver door after ignition OFF Scan tool not communicating with a vehicle control module - in some cases it may need to be disconnected from the DLC All access doors closed Headlamps OFF - auto headlamps disabled Any delay lighting OFF If equipped with an under hood lamp disable it HVAC after blow OFF Any accessory that can work with ignition OFF inactive or OFF Wait up to 2 min or longer, after all other listed conditions are met

Using an Inductive Pickup Probe

Connect an inductive pickup probe to the negative battery cable that can read down to 1 mA.
Ignition OFF, as the vehicle systems shut down test for less than 30 mA of parasitic current drain. If greater than the specified range, refer to Circuit/System Testing below.

Using the EL 38758 Parasitic Draw Test Switch

Ignition OFF, disconnect the battery negative cable from the battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Turn the EL 38758 switch knob to the OFF position.
Install the male end of the EL 38758 switch to the battery ground terminal.
Install the battery negative cable to the female end of the EL 38758 switch.
Turn the EL 38758 switch knob to the ON position.
Road test the vehicle and activate all of the accessories such as the radio and air conditioning.
Ignition OFF, connect a 10 A fused jumper wire to the test switch tool terminals.
Turn the EL 38758 switch knob to the OFF position. The current now flows through the jumper wire.
Check the fuse in the jumper wire. The fuse should be OK. Failed: If the jumper wire fuse is blown, refer to Circuit/System Testing below. Passed
Turn the EL 38758 switch knob to the ON position. Remove the fused jumper wire.
Connect a DMM set to the 10 A DC scale between the test switch tool terminals.
Turn the EL 38758 switch knob to the OFF position. The current now flows through the DMM.
As the vehicle systems shut down test for less than 30 mA of parasitic current drain. If greater than the specified range, refer to Circuit/System Testing below.

Note. Removing or installing a fuse, relay, or connector, to determine the area causing high parasitic draw may wake up control modules. You must wait for the control modules to go back to sleep before retesting. It is best to install any removed or disconnected components after the diagnosis is completed. Fuses for power mode master components such as the BCM should be removed last to avoid misdiagnosis. If a scan tool is connected to the DLC, either disconnect it or subtract the scan tool current draw from the DMM reading to get the actual vehicle parasitic current draw.

If the vehicle has an unacceptable amount of parasitic current draw, remove each fuse one at a time until the current draw falls to an acceptable level. A drop of more than 10-20 mA, when disabling a single system or circuit, is an indication of an overly high current draw that could be causing the battery drain. Refer to Power Distribution Schematics to diagnose exactly which circuit of the suspect system is causing the high parasitic drain. The following is a list of common components that could cause a high current draw

Stuck switch
Stuck relay
Control module

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for control module replacement, programming and setup

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
B+		P0621
Control - L Terminal	P0621	P0621	P0621
Signal - F Terminal	P0622	P0622	P0622	P0622

The engine control module (ECM) uses the generator field duty cycle signal circuit, or F-terminal circuit, to monitor the duty cycle of the generator. The generator field duty cycle signal circuit connects to high side of the field windings in the generator. A pulse width modulated (PWM) high side driver in the voltage regulator turns the field windings on and off. The ECM uses the PWM signal input to determine the generator load on the engine. This allows the ECM to adjust the idle speed to compensate for high electrical loads. The ECM monitors the status of the generator field duty cycle signal circuit. When the ignition is ON and the engine is off, the ECM should detect a duty cycle near 0%. When the engine is running, the duty cycle should be between 5-99%.

Schematic Reference

Connector End View Reference

Description and Operation

Generator Replacement (V6) , Generator Replacement (V8) , Generator Replacement (Diesel)

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Note. Do not have a battery charger connected during the generator testing.

Ignition ON.
Verify that no G13 Generator or B18 Battery Current Sensor DTCs are set that would cause a charging system concern. If DTCs are set Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) . If no DTCs are set
Verify the scan tool Body Control Module Battery Voltage parameter is 12 V or greater. If less than 12 V Refer to «Battery Inspection/Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) . If 12 V or greater
Engine running, all accessories OFF.
Verify the scan tool Body Control Module Battery Voltage parameter continually increases when controlling the Body Control Module Generator Regulator Setpoint from 10% to 80% with a scan tool. It may take up to 10 seconds for the battery voltage to stabilize between each setpoint change. If the battery voltage does not continually increase Refer to Circuit/System Testing below. If the battery voltage continually increases
All OK.

Note. You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

Ignition OFF.
Test for less than 2 ohms between the G13 Generator housing and battery negative terminal. If 2 ohms or greater Repair the open/high resistance in the circuit. If less than 2 ohms
Verify a test lamp illuminates between the G13 Generator B+ circuit terminal 1 X2 and ground. If the test lamp does not illuminate and the circuit fuse is good Remove the test lamp and disconnect the B+ cable at the G13 Generator. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Remove the test lamp, disconnect the battery negative cable, and disconnect the G13 Generator B+ cable. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, test or replace the G13 Generator. If the test lamp illuminates
Test or replace the G13 Generator.

Perform the Diagnostic Repair Verification after completing the repair.

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Noise from a generator may be due to electrical or mechanical noise. Electrical noise or magnetic whine usually varies with the electrical load placed on the generator and is a normal operating characteristic of all generators. When diagnosing a noisy generator, it is important to remember that loose or misaligned components around the generator may transmit the noise into the passenger compartment and that replacing the generator may not solve the problem.

Start the engine. Verify the noise can be heard. Compare the concern to a similar vehicle.
Perform a charging system test. Verify that the generator is charging properly.
Inspect the generator, generator mounting, wiring harness, heater hoses, A/C lines, or other accessory equipment that may be misrouted or be the cause of noise being transmitted into the passenger compartment.
Ignition OFF, remove the engine drive belt. Verify the generator, A/C compressor, water pump pulley, power steering pump, idler pulley, and tensioner pulley spin freely. If any of the pulleys do not spin freely, replace the affected component.
Start the engine, with the drive belt removed. Verify that the noise goes away. Operate the engine for no longer than 30-40 seconds. If the noise is still present, the generator is not the cause of the noise.
Loosen all generator mounting bolts and ensure the generator is properly aligned. Tighten the mounting bolts to specification, refer to «Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Drive Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) for the 4.3L engine
«Drive Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) for the 6.6L Diesel engine
«Drive Belt Replacement - Accessory»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) for the 4.8L or 5.3L engines
«Air Conditioning Compressor Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) for the 4.8L or 5.3L engines
«Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
B+ terminal 30	1	1
ECM Park/ Neutral Signal	2	1
Coil Control terminal 86		1	3
Control Output terminal 87	1	1	3
Coil Ground terminal 85		1
1. No crank 2. Cranks in any gear 3. Cranks all the time

When the ignition switch is placed in the START position, a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the START position. The BCM then sends a message to the engine control module (ECM) that crank has been requested. The ECM then verifies that the transmission is in Park/Neutral. If it is, the ECM then supplies 12 V to the control circuit of the crank relay. When this occurs, battery voltage is supplied through the switch of the crank relay to the starter solenoid.

Schematic Reference

«Starting and Charging Schematics»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Automatic Transmission Controls Schematics»(/chevrolet/express-g1500/2013-2013/remont/automatic-trans/#automatic-transmission-4l60-e-m30-wiring-schematic-diagrams) for the 4L60/4L65/4L70-E transmission.
«Automatic Transmission Controls Schematics»(/chevrolet/express-g1500/2013-2013/remont/automatic-trans/#automatic-transmission-6l90-myd-wiring-schematic-diagrams) for the 6L45/6L50/6L80/6L90 transmission.

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, verify that no crank relay, theft deterrent, or automatic transmission DTCs are set that would cause the ECM not to enable engine starting. If DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
Ignition ON, observe the scan tool BCM Current Power Mode parameter. Place ignition switch in the crank position, the parameter should display Crank Request. If not the specified value, refer to «Power Mode Mismatch»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures) .
Transmission range selector in park, verify the scan tool ECM PNP Switch and TCM Park/Neutral parameters display Park/Neutral. If the TCM parameter does not indicate Park/Neutral. Refer to «Range Selector Displays Incorrect Range»(/chevrolet/express-g1500/2013-2013/remont/automatic-trans/#automatic-transmission-4l60-e-m30-diagnostic-information-and-procedures) , for the 4L60/4L65/4L70-E transmission or «Transmission Internal Mode Switch Logic»(/chevrolet/express-g1500/2013-2013/remont/automatic-trans/#automatic-transmission-6l90-myd-specifications__transmission-internal-mode-switch-logic) for the 6L45/6L50/6L80/6L90 transmission. If the ECM Park/Neutral parameter does not indicate Park/Neutral. Refer to ECM Park Switch Circuit Malfunction below.
Transmission range selector in park or neutral, attempt to start the vehicle. The crank relay should click and the engine should begin cranking. If the crank relay does not click or the engine does not crank, refer to Crank Relay Circuit Malfunction below.
Ignition ON, observe the scan tool ECM Crankshaft Position Sensor Active Counter is not incrementing. If the Crankshaft Position Sensor Active Counter is incrementing, replace the Crankshaft Position Sensor.

ECM Park Switch Circuit Malfunction

Ignition OFF, disconnect the harness connector at the PNP switch harness connector at the transmission.
Ignition ON, install a 3A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool ECM PNP switch parameter displays Park/Neutral. If not the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
If all circuits test normal, test or replace the Park/Neutral position switch.

Crank Relay Circuit Malfunction

Ignition OFF, disconnect the crank relay.
Ignition OFF, test for less than 5.0 ohms between the relay ground circuit terminal 85 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
Ignition ON, verify a test lamp illuminates between the relay switch B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
Ensure the parking brake is applied and the transmission is in PARK.
Momentarily install a 40A fused jumper wire between the B+ circuit terminal 30 and the control output circuit terminal 87.
The starter solenoid should engage and the engine should begin cranking. If the solenoid does not engage, test the control output circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the starter motor.
Connect a test lamp between the coil control circuit terminal 86 and the coil ground circuit terminal 85.
With the transmission range selector in park or neutral, cycle the ignition between the OFF and CRANK position. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
If all circuits test normal, test or replace the crank relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Crankshaft Position Sensor Replacement»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-43-lu3-repair-instructions) for the 4.3L engine
«Crankshaft Position Sensor Replacement»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controlsfuel-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions) for the 4.8L, 5.3L, 6.0L, 6.2L or 7.0L engines
«Crankshaft Position Sensor Replacement»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) for the 6.6L (LGH or LML) engine
«Relay Replacement (Within an Electrical Center)»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) , «Relay Replacement (Attached to Wire Harness)»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
«Transmission Internal Mode Switch Logic»(/chevrolet/express-g1500/2013-2013/remont/automatic-trans/#automatic-transmission-4l60-e-m30-specifications__transmission-internal-mode-switch-logic) for the 4L60/4L65/4L70-E transmission
«Automatic Transmission Controls Schematics»(/chevrolet/express-g1500/2013-2013/remont/automatic-trans/#automatic-transmission-6l90-myd-wiring-schematic-diagrams) for the 6L45/6L50/6L80/6L90 transmission.
«Starter Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Starter Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Starter Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Control Module References»(/chevrolet/express-g1500/2013-2013/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup and programming

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition OFF, measure and record the battery voltage at the terminals. The voltage should be between 12.0-15.0 V. If not within the specified range, refer to «Battery Inspection/Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the drive belts. Refer to one of the following: «Drive Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) for the 4.3L engine «Drive Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) for the 6.6L Diesel engine «Drive Belt Replacement - Accessory»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) for the 4.8L or 5.3L engines «Air Conditioning Compressor Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) for the 4.8L or 5.3L engines
Using the appropriate tools, rotate the crankshaft by hand and verify the crankshaft rotates. If the crankshaft does not rotate, refer to one of the following: «Engine Will Not Crank - Crankshaft Will Not Rotate»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3__engine-will-not-crank-crankshaft) for the 4.3L engine «Engine Will Not Crank - Crankshaft Will Not Rotate»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-diagnostic-information-and-procedures__engine-will-not-crank-crankshaft) for the 6.6L Diesel engine «Engine Will Not Crank - Crankshaft Will Not Rotate»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-diagnostic-information-and-procedures__engine-will-not-crank-crankshaft) for the 4.8L or 5.3L engines
Ignition start, verify the engine does not crank. If the engine cranks, inspect the engine and belt drive system for mechanical binding, seized engine, or seized generator.
Verify that a test lamp illuminates between the starter motor B+ terminal B X1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
Test for less than 0.5 V between the positive battery cable and terminal B X1 at the starter motor as ignition is switched to start position. If greater than the specified value, replace the positive battery cable.
Test for less than 0.5 V between the negative battery cable and the starter motor case as ignition is switched to start position. If greater than the specified value, replace the negative battery cable.
If all circuits test normal, replace the starter motor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Battery Negative Cable Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Negative Cable Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Negative Cable Replacement (LGH-Primary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Battery Positive Cable Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (LGH-Primary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (LGH-Auxiliary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Starter Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Starter Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Starter Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

«Circuit Testing»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Wiring Repairs»(/chevrolet/express-g1500/2013-2013/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition OFF, measure and record the battery voltage at the terminals. The voltage should be between 12.0-15.0 V. If not within the specified range, refer to «Battery Inspection/Test»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the drive belts. Refer to one of the following: «Drive Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) for the 4.3L engine «Drive Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) for the 6.6L Diesel engine «Drive Belt Replacement - Accessory»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) for the 4.8L or 5.3L engines «Air Conditioning Compressor Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) for the 4.8L or 5.3L engines
Ignition Start, verify the engine does not crank normal. If the engine cranks normal, inspect the engine and belt drive system for mechanical binding, seized engine, or seized generator.
Verify that a test lamp illuminates between the starter motor B+ terminal B X1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
Test for less than 0.5 V between the positive battery cable and terminal B X1 at the M64 starter motor as ignition is switched to start position. If greater than the specified value, replace the positive battery cable.
Test for less than 0.5 V between the negative battery cable and the starter motor case as ignition is switched to start position. If greater than the specified value, replace the negative battery cable.
If all circuits test normal, replace the starter motor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Battery Positive Cable Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (LGH-Primary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (LGH-Auxiliary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Battery Negative Cable Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Negative Cable Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Negative Cable Replacement (LGH-Primary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
«Starter Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Starter Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Starter Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)

Perform the «Diagnostic System Check - Vehicle»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/chevrolet/express-g1500/2013-2013/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Remove the flywheel inspection cover.
Inspect the flywheel for the following: Loose flywheel bolts Chipped gear teeth Missing gear teeth Bent flywheel If not within specifications, secure the flywheel bolts or replace the flywheel. If all inspections were within specification, replace the starter motor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fastener Tightening Specifications»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3__fastener-tightening-specifications) , for the 4.3 L engine, «Fastener Tightening Specifications»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-specifications__fastener-tightening-specifications) , for V8 gas engines or «Fastener Tightening Specifications»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-specifications__fastener-tightening-specifications) for the 6.6 L engine
«Engine Flywheel Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) , for the 4.3 L engine, «Automatic Transmission Flex Plate Removal»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-off-vehicle__automatic-transmission-flex-plate-removal) , for V8 gas engines or «Engine Flywheel Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle__engine-flywheel-replacement) for the 6.6 L engine
«Starter Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Starter Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Starter Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)

Removal Procedure

Turn OFF all the lamps and accessories.
Turn the ignition OFF.
Remove the battery negative cable bolt in order to disconnect the negative battery cable from the battery.
Remove the auxiliary negative battery cable bolt (1) and cable (2), from the auxiliary battery.

Installation Procedure

Install the negative cable terminal bolt and cable to the battery and Tighten to 14 N.m (123 lb in).
If applicable, install the auxiliary negative cable terminal bolt (1) and cable (2) to the auxiliary battery and tighten to 14 N.m (123 lb in).

Disconnect the instrument panel (I/P) harness electrical connector (1) from the battery current sensor.
Remove the negative battery cable. Refer to «Battery Negative Cable Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Negative Cable Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Negative Cable Replacement (LGH-Primary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Cut the tie straps and electrical tape attaching the battery current sensor to the battery cable.
Squeeze the negative battery cable branches together.
Slide the battery current sensor (1) off of the negative battery cable.

Slide the NEW battery current sensor (1) up onto the negative battery cable.
Using NEW tie straps and electrical tape, attach the battery current sensor to the negative battery cable.
Install the negative battery cable. Refer to «Battery Negative Cable Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Negative Cable Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Negative Cable Replacement (LGH-Primary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Connect the I/P harness electrical connector to the battery current sensor.

On all models, disconnect the battery negative cable from the battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Disconnect the battery negative cable lead from the inner fender panel.
On models with 5.3L engine, disconnect the battery negative cable lead from the frame.
On all models, disconnect the battery negative cable lead from the engine block.
On models with 4.8L and 6.0L engine, disconnect the battery negative cable lead from the frame.
On all models, remove the battery negative cable from the vehicle.

On all models, install the negative cable to the vehicle.
On models with 4.8L and 6.0L engine, connect the negative cable to the frame.
On all models, connect the negative cable to the engine block and tighten the bolt to 25 N.m (18 lb ft).
On models with 5.3L engine, connect the negative cable lead to the frame.
On all models, connect the negative cable lead to the inner fender panel and tighten the nut to 10 N.m (89 lb in).
Connect the negative cable to the battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Disconnect the battery current sensor (1) harness connector.
Remove the negative battery cable ground bolt (2) from the inner fender panel.
Remove the negative battery cable ground lead (3) from the inner fender panel.
Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g1500/2013-2013/remont/hoistjack/#general-information) .
Remove the negative battery cable ground lead bolt (2) at the crossmember.
Remove the negative battery cable ground (1) from the crossmember.
Remove the negative battery cable ground bolt (2) from the engine block.
Remove the negative battery cable ground (1) from the block.
Lower the vehicle.
Remove the negative battery cable from the vehicle.

Install the negative battery cable to the vehicle.
Raise the vehicle.
Position the negative cable ground lead (1) to the engine block.
Install the negative cable ground bolt (2) to the engine block and tighten the bolt to 25 N.m (18 lb ft).
Install the negative cable ground lead (1) to the crossmember.
Install the negative cable ground bolt (2) at the crossmember and tighten to 10 N.m (89 lb in).
Lower the vehicle.
Position the negative cable ground (3) to the inner fender panel.
Install the negative cable ground bolt (2) to the inner fender panel and tighten to 14 N.m (123 lb in).
Connect the battery current sensor (1) harness connector.
Connect the negative cable to the battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Disconnect the battery negative cable from the battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the battery negative cable ground bolt (1) and terminal (2), from the inner fender panel.
Remove the battery negative frame ground bolt (1) and terminal (2), from the right chassis frame.
Disconnect the battery negative cable engine ground bolt (1) and terminal (2) from the right side engine block.
Remove the battery negative cable from the vehicle.

Install the battery negative terminal (2) to the right frame rail and tighten bolt (1) to 25 N.m (18 lb ft)
Connect the battery negative cable lead (2) to the engine block and tighten bolt (1) to 25 N.m (18 lb ft).
Install the battery negative cable terminal (2) to the right inner fender and tighten bolt (1) to 14 N.m (9 lb ft)
Connect the negative cable to the battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g1500/2013-2013/remont/hoistjack/#general-information) .
Disconnect the auxiliary battery negative cable from the auxiliary battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Disconnect the auxiliary battery negative ground bolt (1) from the frame.
Remove the auxiliary battery negative cable (2) from the vehicle.

Install the auxiliary battery negative cable to the vehicle.
Connect the auxiliary negative ground terminal bolt (1) to the frame and tighten to 10 N.m (89 lb in).
Connect the auxiliary battery negative cable (2) to the auxiliary battery and tighten to 14 N.m (123 in lb).

On all models, remove the bolt retaining the coolant recovery reservoir or surge tank.
Position the coolant recovery reservoir or the surge tank aside.
Disconnect the battery negative cable from the battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Disconnect the battery positive cable from the battery.
On models equipped with the 4.8L, or 6.0L engine, disconnect the positive lead to the junction block.
On models equipped with 4.8L, 5.3L or 6.0L engine, unclip the battery positive cable from the engine harness clip (1).
Unclip the battery positive cable from the engine harness retainer (2).
On all models, raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g1500/2013-2013/remont/hoistjack/#general-information) .
Disconnect the positive lead at the starter solenoid.
On models with 4.8L and 6.0L engine, remove the battery positive cable retainer clips (1).
Remove the positive cable to the chassis harness clips (2).
Remove the positive cable retainer clips (1) from the frame.
Remove battery positive cable retainer clips (2) from crossmember.
On all models, lower the vehicle.
On models equipped with the 4.8L, 5.3L or 6.0L engine, unclip the battery positive cable from the fan shroud.
On all models, disconnect the positive lead to the generator.
Remove the positive cable from the vehicle. Note the location of the retaining clips.

On all models, install the positive cable to the vehicle. Ensure the cable is routed correctly and installed in the retainer clips.
Connect the positive lead to the generatoroutput (BAT) terminal and tighten the nut to 10 N.m (89 lb in).
On models equipped with the 4.8L, 5.3L or 6.0L engine, clip the positive cable to the fan shroud.
On all models, raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g1500/2013-2013/remont/hoistjack/#general-information) .
On models with 4.8L and 6.0L engine, install the positive cable retainer clips (2) to the crossmember.
Install the positive cable retainer clips (1) to the frame.
Install the positive cable to the chassis harness clips (2).
Install the positive cable retainer clips (1).
Install the positive lead to the starter solenoid and tighten the nut to 10 N.m (89 lb in).
On all models, lower the vehicle.
On models equipped with 4.8L, 5.3L or 6.0L engine, clip battery positive cable to the engine harness retainer (2).
Clip the positive cable to the engine harness clip (1).
On models equipped with the 4.8L, or 6.0L engine, install the positive lead to the junction block and tighten the nut to 10 N.m (89 lb in).
On all models, connect the battery positive cable to the battery and tighten to 14 N.m (123 lb in).
Connect the battery negative cable to the battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Install the coolant recovery reservoir or surge tank and tighten the bolt to 11 N.m (97 lb in).

Unbolt and reposition the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g1500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Loosen the positive battery cable bolt (4) in order to disconnect the positive battery cable (3) from the battery.
Remove the nut (2) retaining the positive battery cable terminal (1) to the junction block.
Remove the positive battery cable clip (5) from the battery tray.
Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g1500/2013-2013/remont/hoistjack/#general-information) .
Remove the positive battery cable retainer (2) to frame bolt (1).
Remove the battery terminal nut (3) on the starter solenoid (1).
Remove the positive battery cable (2) from the starter solenoid.
Lower the vehicle.
Reposition the positive battery cable boot (2) at the generator.
Remove the generator nut (3).
Remove the positive battery cable (1) from the generator.
Remove the positive battery cable from the vehicle.

Install the positive battery cable to the vehicle.
Install the positive cable (1) to the generator.
Install the generator nut (3) and tighten to 10 N.m (89 lb in).
Position the positive cable boot (2) at the generator.
Raise and support the vehicle.
Install the battery positive terminal (2) to the starter solenoid.
Install the battery terminal nut (3) onto the starter solenoid battery terminal (1) and tighten to 10 N.m (89 lb in).
Install the positive cable retainer (2) to frame bolt (1) and tighten to 13 N.m (115 lb in).
Lower the vehicle.
Install the positive battery cable (1) to the junction block and tighten to 13 N.m (115 lb in).
Install the positive battery cable clip (5) from the battery tray.
Install the positive battery cable to the battery and tighten the bolt to 14 N.m (123 lb in).
Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Install the coolant recovery reservoir. Refer to «Coolant Recovery Reservoir Replacement»(/chevrolet/express-g1500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .

Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Disconnect the positive battery cable from the battery.
Remove the positive cable nut from the junction block and disconnect the cable.
Remove the positive cable nut from the generator and disconnect the cable.
Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/express-g1500/2013-2013/remont/exteriorinterior-trim/#interior-trim-and-interior-paneling) .
Disconnect the wiring harness clips and the positive cable from the glow plug module.
Remove the battery positive cable from the engine harness clip.
Remove the battery positive cable from the engine harness clips (1).
Raise the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g1500/2013-2013/remont/hoistjack/#general-information) .
Remove the battery positive cable bolt (1) and clip (2) from the frame.
Remove the battery positive cable retaining clip from the transmission line bracket.
Remove the positive battery cable nut (7) from the starter and disconnect the cable (8).
Remove the positive battery cable.

Position the positive cable to the vehicle using the same cable routing as in removal.
Position the positive cable (8) to the starter and install the nut (7) and tighten to 10 N.m (89 lb in).
Install the positive cable retaining clip to the transmission line bracket.
Install the battery positive cable nut (1) and clip (2) to the frame.
Lower the vehicle.
Install the positive cable to engine harness clips (1).
Install the positive cable to the engine harness clip.
Connect the positive cable to the glow plug module and connect the wiring harness clips.
Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/express-g1500/2013-2013/remont/exteriorinterior-trim/#interior-trim-and-interior-paneling) .
Install the positive battery cable to the generator and tighten the nut 10 N.m (89 lb in).
Install the positive cable to the junction block and tighten the nut to 8 N.m (71 lb in).
Connect the positive cable to the battery and tighten the terminal to 14 N.m (123 lb in).
Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

WARNING

Disconnect the auxiliary battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the auxiliary positive battery cable to the frame clips (1).
Remove the auxiliary positive battery cable to chassis harness clips (2).
Remove the auxiliary positive battery cable to frame clips (1).
Remove the auxiliary positive battery cable to crossmember clips (2).
Remove the auxiliary positive battery cable to frame clip (3).
Remove the auxiliary positive battery cable nut from the junction block.
Disconnect the auxiliary positive battery cable wiring harness clips.
Remove the auxiliary positive battery cable from the vehicle.

Position the auxiliary positive battery cable and connect the wiring harness clips.
Position the auxiliary positive battery cable to the junction block and tighten the cable nut to 8 N.m (71 lb in).
Install the auxiliary positive battery cable to frame clip (3).
Install the auxiliary positive battery cable to crossmember clips (2).
Install the auxiliary positive battery cable to frame clips (1).
Install the auxiliary positive battery cable to the chassis harness clips (2).
Install the auxiliary positive battery cable to the frame clips (1).
Connect the auxiliary positive battery cable to the auxiliary battery and tighten the terminal to 14 N.m (123 lb in).
Connect the auxiliary negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

WARNING

Disconnect the auxiliary battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the auxiliary positive battery cable to the frame clips (1).
Remove the auxiliary positive battery cable to chassis harness clips (2).
Remove the auxiliary positive battery cable to frame clips (1).
Remove the auxiliary positive battery cable to crossmember clips (2).
Remove the auxiliary positive battery cable to frame clip (3).
Remove the auxiliary positive battery cable nut from the junction block.
Disconnect the auxiliary positive battery cable wiring harness clips.
Remove the auxiliary positive battery cable from the vehicle.

Position the auxiliary positive battery cable and connect the wiring harness clips.
Position the auxiliary positive battery cable to the junction block and tighten the cable nut to 8 N.m (71 lb in).
Install the auxiliary positive battery cable to frame clip (3).
Install the auxiliary positive battery cable to crossmember clips (2).
Install the auxiliary positive battery cable to frame clips (1).
Install the auxiliary positive battery cable to the chassis harness clips (2).
Install the auxiliary positive battery cable to the frame clips (1).
Connect the auxiliary positive battery cable to the auxiliary battery and tighten the terminal to 14 N.m (123 lb in).
Connect the auxiliary negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

WARNING

Remove the auxiliary positive battery cable (1) from the auxiliary battery.
Remove the auxiliary battery positive retainer clips (2) securing the harness to the frame.
Remove the auxiliary positive battery cable to frame clips (1).
Remove the auxiliary positive battery cable to crossmember clips (2).
Remove the auxiliary positive battery cable to frame clip (3).
Remove the auxiliary positive battery cable nut from the junction block.
Disconnect the auxiliary positive battery cable wiring harness clips.
Remove the auxiliary positive battery cable from the vehicle.

Position the auxiliary positive battery cable and connect the wiring harness clips.
Position the auxiliary positive battery cable to the junction block and tighten the cable nut to 8 N.m (71 lb in).
Install the auxiliary positive battery cable to frame clip (3).
Install the auxiliary positive battery cable to crossmember clips (2).
Install the auxiliary positive battery cable to frame clips (1).
Install the auxiliary battery positive cable to the frame with the retainers (2).
Connect the auxiliary positive battery cable (1) to the auxiliary battery and tighten the terminal to 14 N.m (123 lb in).
Connect the auxiliary negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Disconnect the auxiliary battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the positive extension cable nut from the junction block and disconnect the cable.
Remove the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
Remove the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
Remove the positive extension cable nut from the intake air heater and disconnect the cable.
Disconnect the wiring harness clips.
Remove the battery positive cover from the underhood bused electrical center (UBEC).
Remove the positive extension cable nut from the UBEC terminal stud.
Remove the positive extension cable.

Position the positive extension cable and connect the wiring harness clips.
Position the positive extension cable to the UBEC terminal stud and tighten the nut to 9 N.m (80 lb in).
Install the battery positive cover to the UBEC.
Position the positive extension cable to the intake air heater and tighten the nut to 4 N.m (34 lb in).
Install the air cleaner outlet duct. Refer to «Air Cleaner Outlet Duct Replacement»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
Install the air cleaner assembly. Refer to «Air Cleaner Assembly Replacement»(/chevrolet/express-g1500/2013-2013/remont/testing-diagnostics/#engine-controls-and-fuel-66l-lgh-repair-instructions) .
Position the positive extension cable to the junction block and tighten the cable nut to 8 N.m (71 lb in).
Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Scheme 5

Scheme 5: Generator Cable Replacement

Callout	Component Name
Preliminary Procedure Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .
1	Nut CAUTION: Refer to Fastener Caution . Tighten 12 N.m (9 lb ft)
2	Generator Cable Terminal (Generator)
3	Nut Tighten 10 N.m (7 lb ft)
4	Generator Cable Terminal (Battery Positive Junction Block)
5	Generator Cable

CAUTION
Refer to Fastener Caution .

Generator Cable Replacement

WARNING

Batteries produce explosive gases. Batteries contain corrosive acid. Batteries supply levels of electrical current high enough to cause burns. Therefore, in order to reduce the risk of personal injury while working near a battery, observe the following guidelines: Always shield your eyes. Avoid leaning over the battery whenever possible. Do not expose the battery to open flames or sparks. Do not allow battery acid to contact the eyes or the skin. Flush any contacted areas with water immediately and thoroughly. Get medical help.

Remove the fender brace.
Disconnect the battery negative cable from the negative battery terminal. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Disconnect the battery positive cable from the positive battery terminal. Refer to «Battery Positive Cable Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (LGH-Primary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (LGH-Auxiliary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the battery hold-down retainer bolt and retainer.
Remove the battery from the vehicle.
Inspect the battery for: Damage Worn or corroded cables and connectors Damage or foreign objects in the battery carrier
If damage is noted, find and correct the cause.
Clean any corrosion form the battery cables and connectors.
Clean the battery tray and remove any foreign objects from the tray.

Install the battery into the battery tray.
Install the battery hold-down retainer and bolt and tighten to 18 N.m (12 lb ft).
Connect the battery positive cable and the positive battery cable terminal to the battery. Refer to «Battery Positive Cable Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (LGH-Primary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (LGH-Auxiliary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Connect the battery negative cable and the negative battery cable terminal to the battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Install the fender brace.

Remove the coolant recovery reservoir bolt and reposition the reservoir.
Disconnect the battery negative cable from the battery negative terminal. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Disconnect the battery positive cable from the battery positive terminal. Refer to «Battery Positive Cable Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (LGH-Primary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Battery Positive Cable Replacement (LGH-Auxiliary)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the battery limiter from the vehicle if equipped.
Remove the fender brace.
Remove the battery hold-down bolt and retainer.
Remove the battery.
Remove the battery tray bolts.
Disconnect the vacuum hoses.
Disconnect the vacuum pump electrical connector.
Remove the battery tray from the vehicle.

Install the battery tray to the vehicle.
Connect the vacuum pump hoses and electrical connector.
Install the battery tray bolts and tighten to 9 N.m (80 lb in).
Install the battery.
Install the battery hold-down retainer and bolt and tighten to 18 N.m (12 lb ft).
Install the fender brace.
Install the battery limiter to the vehicle if equipped.
Install the positive battery cable to the battery and tighten to 17 N.m (13 lb ft).
Install the battery negative cable to the battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) . Tighten the terminal bolt to 17 N.m (13 lb ft).
Install the coolant recovery reservoir and tighten to 11 N.m (97 lb in).

Disconnect the primary battery and the auxiliary battery negative cables. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)
Disconnect the auxiliary battery positive cable from the auxiliary battery.
Remove the lower auxiliary battery tray to frame bolts (3).
Loosen, but DO NOT REMOVE the upper battery tray to frame bolts (1).
Lift the battery and tray assembly (2) from the upper frame bolts (1).
Remove the battery retainer bolt and retainer (3).
Remove the battery (1) from the battery tray (2).

Install the battery (1) into the battery tray (2).
Install the battery bolt and retainer (3) and tighten to 18 N.m (12 lb ft).
Lift the battery and tray assembly (2) onto the upper auxiliary battery tray bolts (1). Do not tighten the upper bolts at this time.
Install the lower battery tray bolts (3) and tighten to 25 N.m (18 lb ft).
Connect the positive battery cable to the auxiliary battery and tighten the bolt to 14 N.m (123 lb in).
Connect the negative battery cable to the auxiliary battery and to the primary battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Disconnect the primary battery and the auxiliary battery negative cable (1). Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Disconnect the auxiliary battery positive cable fastener (2) from the auxiliary battery.
Remove the lower battery tray bolts (3) from the chassis frame.
Loosen the upper auxiliary battery tray bolts (1).
Lift the auxiliary battery tray (2) and battery from the upper frame bolts (1).
Remove the battery retainer bolt and retainer (3).
Remove the battery (1) from the battery tray (2).

Install the battery (1) into the battery tray (2).
Install the battery bolt and retainer (3) and tighten to 18 N.m (12 lb ft).
Lift the auxiliary battery and tray assembly (2) onto the battery tray bolts (1). Do not tighten the upper bolts at this time.
Install the lower battery tray bolts (3) and tighten to 25 N.m (18 lb ft).
Tighten the upper bolts (1) to 25 N.m (18 lb ft).
Connect the auxiliary positive battery cable (3) to the auxiliary battery and tighten the fastener (2) to 14 N.m (123 lb in).
Connect the auxiliary negative battery cable fastener (1) to the auxiliary battery and to the primary battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Remove the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/express-g1500/2013-2013/remont/exteriorinterior-trim/#interior-trim-and-interior-paneling) . Remove the engine wiring harness ground bolt.
Reposition the engine wiring harness ground and ground strap.
Remove the ground strap nut from the stud at the front of dash.
Remove the ground strap from the stud.

Install the ground strap to the stud.
Install the ground strap nut to the stud at the front of dash and tighten to 9 N.m (80 lb in).
Position the ground strap and engine wiring harness ground.
Install the engine wiring harness ground bolt and tighten to 16 N.m (12 lb ft).
Install the engine cover. Refer to «Engine Cover Replacement»(/chevrolet/express-g1500/2013-2013/remont/exteriorinterior-trim/#interior-trim-and-interior-paneling) .

WARNING

Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/express-g1500/2013-2013/remont/hoistjack/#general-information) .
Remove the right transmission cover bolt, if equipped.
Disconnect the oil level sensor electrical connector.
Remove the starter bolts.
Slide the starter forward until the starter clears the transmission.
Remove the starter solenoid nut.
Remove the starter lead from the solenoid stud.
Remove the starter lead nut.
Remove the positive cable from the starter stud.
Place the starter on a workbench.
Unsnap the transmission cover from the starter, if equipped.
If necessary, remove the starter shield.

If necessary, install the starter shield.
Snap the transmission cover to the starter, if equipped.
Install the positive cable to the starter stud.
Install the starter lead nut and tighten to 10 N.m (89 lb in)..
Install the starter solenoid lead to the solenoid stud.
Install the starter solenoid nut and tighten to 3.4 N.m (30 lb in).
Slide the starter rearward.
Install the starter bolts and tighten to 50 N.m (37 lb ft).
Install the right transmission cover bolt, if equipped and tighten to 9 N.m (80 lb in).
Connect the oil level sensor electrical connector.
Lower the vehicle.
Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Scheme 6

Scheme 6: Starter Replacement (V6)

Callout	Component Name
Preliminary Procedures Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle
1	Battery Terminal Nut CAUTION: Refer to Fastener Caution . Tighten 9 N.m (80 lb in)
2	Starter Bolt (Qty: 2) Tighten 50 N.m (37 lb ft)
3	Starter Procedure Disconnect the S terminal harness connector from the starter. NOTE: Orient the B+ terminal Harness anti rotation tab to the starter orientation slot. Remove the B+ terminal harness from the starter. NOTE: The starter motor bracked shield snaps into place on the starter solenoid. Remove the starter motor bracket shield from the starter.

CAUTION
Refer to Fastener Caution .

NOTE
Orient the B+ terminal Harness anti rotation tab to the starter orientation slot.

NOTE
The starter motor bracked shield snaps into place on the starter solenoid.

Starter Replacement (V6)

Scheme 7

Scheme 7: Starter Replacement (Diesel)

Callout	Component Name
Preliminary Procedures Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection . Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle . Reposition the transmission cooler lines. Refer to Transmission Fluid Cooler Hose/Pipe Replacement (4L60-E/4L65-E/4L70-E) , Transmission Fluid Cooler Hose/Pipe Replacement (6L90 MYD) .
1	Starter Solenoid Cable Nut CAUTION: Refer to Fastener Caution . Tighten 9 N.m (80 lb in)
2	Engine Harness Starter Solenoid Nut Tighten 3.4 N.m (30 lb in)
3	Engine Harness
4	Battery Positive Cable
5	Starter Bolts (Qty: 2) Tighten 78 N.m (58 lb ft)
6	Starter

CAUTION
Refer to Fastener Caution .

Starter Replacement (Diesel)

Remove the generator. Refer to «Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the power steering pump. Refer to «Power Steering Pump Replacement (4.3L)»(/chevrolet/express-g1500/2013-2013/remont/manual-power-steering/#power-steering-system) , «Power Steering Pump Replacement (4.8L, 5.3L, 6.0L)»(/chevrolet/express-g1500/2013-2013/remont/manual-power-steering/#power-steering-system) , «Power Steering Pump Replacement (LGH)»(/chevrolet/express-g1500/2013-2013/remont/manual-power-steering/#power-steering-system) .
Remove the generator bracket bolts.
Remove the generator bracket.

Install the generator bracket.
Install the generator bracket bolts and tighten to 50 N.m (37 lb ft).
Install the power steering pump. Refer to «Power Steering Pump Replacement (4.3L)»(/chevrolet/express-g1500/2013-2013/remont/manual-power-steering/#power-steering-system) , «Power Steering Pump Replacement (4.8L, 5.3L, 6.0L)»(/chevrolet/express-g1500/2013-2013/remont/manual-power-steering/#power-steering-system) , «Power Steering Pump Replacement (LGH)»(/chevrolet/express-g1500/2013-2013/remont/manual-power-steering/#power-steering-system) .
Install the generator. Refer to «Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Remove the generator. Refer to «Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the drive belt tensioner. Refer to «Drive Belt Tensioner Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) .
Remove the generator bracket bolts and nut.
Remove the generator bracket.

Install the generator bracket.
Install the generator bracket bolts and nut and tighten to 41 N.m (30 lb ft).
Install the drive belt tensioner. Refer to «Drive Belt Tensioner Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) .
Install the generator. Refer to «Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the fan assembly. Refer to fan replacement «Fan Replacement»(/chevrolet/express-g1500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
Remove the engine harness retainer nut (1) and engine harness ground terminal bolt (3). Reposition engine harness and ground terminal (2).
Reposition the oil level indicator tube. Refer to «Oil Level Indicator Tube Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
Remove the drive belt tensioner. Refer to «Drive Belt Tensioner Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
Remove the generator. Refer to «Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the inlet pipe bracket bolts (1) from the generator bracket and the inlet manifold tube.
Remove the generator bracket nuts (1) and bolt (2) from the cylinder block. Remove the generator bracket (3).
If replacing the generator bracket, remove the idler pulleys (4) and transfer to the new generator bracket.

Position the generator bracket to the engine and install the nuts (1) and bolt (2). Tighten to 50 (37 lb ft).
Install the inlet pipe bracket bolts (1) to the generator bracket and intake manifold tube. Tighten to 25 (17 lb ft).
Install the oil level indicator tube. Refer to «Oil Level Indicator Tube Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
Install the engine harness retainer bracket and nut (1). Tighten to 25 (17 lb ft).
Install the engine harness ground terminal (2) and bolt (3). Tighten to 25 (17 lb ft).
Install the drive belt tensioner. Refer to «Drive Belt Tensioner Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
Install the generator. Refer to «Generator Replacement (V6)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (V8)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) , «Generator Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Install the fan assembly. Refer to «Fan Replacement»(/chevrolet/express-g1500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Scheme 8

Scheme 8: Auxiliary Generator Bracket Replacement (LGH)

Callout	Component Name
Preliminary Procedures Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection . Remove the auxiliary generator. Refer to Auxiliary Generator Replacement
1	Auxiliary Generator Bracket Bolt CAUTION: Refer to Fastener Caution . Tighten 50 N.m (37 lb ft)
2	Auxiliary Generator Bracket

CAUTION
Refer to Fastener Caution .

Auxiliary Generator Bracket Replacement (LGH)

Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) .
Unbolt and reposition the oil level indicator tube. Refer to «Oil Level Indicator Tube Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) .
Unbolt and reposition the oil fill tube. Refer to «Oil Filler Tube Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) .
Disconnect the engine wiring harness electrical connector (1) from the generator.
Remove the oil fill tube bracket stud (2).
Reposition the engine wiring harness clip.
Reposition the positive battery cable boot (2) at the generator.
Remove the generator nut (3).
Remove the positive battery cable (1) from the generator.
Remove the oil fill tube bracket bolt (2) and bracket (1).
Remove the generator bolts (2) and generator (1).

Install the generator (1) and bolts (2) and tighten to 50 N.m (37 lb ft).
Install the oil fill tube bracket (1) and bolt (2) and tighten to 25 N.m (18 lb ft).
Install the positive cable (1) to the generator.
Install the generator nut (3) and tighten to 12 N.m (106 lb in).
Position the positive cable boot (2) at the generator.
Position the engine wiring harness clip to the generator bracket.
Install the oil fill tube bracket stud (2) and tighten to 25 N.m (18 lb ft).
Connect the engine wiring harness electrical connector (1) to the generator.
Position and install the oil fill tube. Refer to «Oil Filler Tube Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) .
Position and install the oil level indicator tube. Refer to «Oil Level Indicator Tube Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) .
Install the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-43l-lu3) .
Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the accessory drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) .
Disconnect the generator electrical connector (3).
Remove the generator cable from the generator, perform the following: Slide the boot down revealing the terminal stud. Remove the generator cable nut from the terminal stud. Remove the generator cable.
Remove the generator bolts.
Remove the generator from the bracket.

Install the generator to the bracket.
Install the generator bolts and tighten to 50 N.m (37 lb ft).
Install the generator cable to the generator, perform the following: Install the generator cable. Install the generator cable nut to the terminal stud and tighten to 9 N.m (80 lb in). Slide the boot over the terminal stud.
Connect the generator electrical connector (3).
Install the accessory drive belt. Refer to «Drive Belt Replacement - Accessory»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-48l-l20-53l-lmf-or-60l-l96-lc8-repair-instructions-on-vehicle) .
Connect the negative battery cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .

Disconnect the negative battery. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system) .
Remove the upper fan shroud. Refer to «Engine Coolant Fan Upper Shroud Replacement (4.3L, 4.8L, 5.3L, 6.0L, 6.2L, 7.0L)»(/chevrolet/express-g1500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Engine Coolant Fan Upper Shroud Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
Remove the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
Remove the generator mounting bolts (1) and the lower generator bracket bolts (2).
Remove the lower generator bracket (3).
Slide the generator (3) towards the front to access the electrical connections.
Remove the generator B + protective boot at the back of the generator.
Remove the generator cable nut (1) and the generator cable terminal (2) from the B + stud.
Disconnect the engine harness connector (4).
Slide the generator (1) forward and remove the generator from the engine compartment.

Install the generator (1) into position on the generator bracket.
Install the generator cable terminal (2) to the generator stud and tighten the nut (1) to 10 (89 lb in).
Connect the engine harness connector (4) and slide the generator (3) back into position on the generator bracket.
Install the lower generator bracket (3) with the generator mounting bolts (1) and tighten to 50 (37 lb ft).
Install the lower generator bracket bolts (2) and tighten to 50 (37 lb ft).
Slide the protective boot back onto the terminal stud.
Install the drive belt. Refer to «Drive Belt Replacement»(/chevrolet/express-g1500/2013-2013/remont/mechanical/#engine-mechanical-66l-lgh-repair-instructions-on-vehicle) .
Install the upper fan shroud. Refer to «Engine Coolant Fan Upper Shroud Replacement (4.3L, 4.8L, 5.3L, 6.0L, 6.2L, 7.0L)»(/chevrolet/express-g1500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) , «Engine Coolant Fan Upper Shroud Replacement (Diesel)»(/chevrolet/express-g1500/2013-2013/remont/cooling-system-mechanical/#engine-cooling-system) .
Connect the battery negative cable. Refer to «Battery Negative Cable Disconnection and Connection»(/chevrolet/express-g1500/2013-2013/remont/charging-system/#battery-charging-system-and-starting-system)

WARNING